The invention provides a nanoscale crystalline silicon powder and the preparation and use thereof.
It is known that an aggregated nanoscale silicon powder can be prepared in a hot wall reactor (Roth et al., Chem. Eng. Technol. 24 (2001), 3). The disadvantage of this process has proven to be that the desired crystalline silicon is produced along with amorphous silicon which is formed by the reaction of silane at the hot reactor walls. In addition, the crystalline silicon has a low BET surface area of less than 20 m2/g and thus is generally too coarse for electronic applications.
Furthermore, Roth et al. do not disclose a process in which doped silicon powders are obtained. Such doped silicon powders, with their semiconductor properties, are very important in the electronics industry. Furthermore, it is a disadvantage that silicon powder is deposited on the reactor walls and acts as a thermal insulator. This changes the temperature profile in the reactor and thus also changes the properties of the silicon powder.